US3037120A

US3037120A - Storage arrangement

Info

Publication number: US3037120A
Application number: US819948A
Authority: US
Inventors: Jr John D Mcdaniels
Original assignee: Babcock and Wilcox Co
Current assignee: Babcock and Wilcox Co
Priority date: 1959-06-12
Filing date: 1959-06-12
Publication date: 1962-05-29
Anticipated expiration: 1979-05-29
Also published as: GB886294A

Description

STORAGE ARRANGEMENT 2 Sheets-Sheet 1 Filed June 12, 1959 FIG. 1

in w

INVENTOR.

John 0. Mc. Daniels Jr.

ATTORNEY M y 6 4. D. MCDANIELS, JR 3,037,120

' STORAGE ARRANGEMENT mm 1: m) mum INVENTOR.

ATTORNEY John D. Mc Daniels, Jr.

3,037,120 STORAGE ARRANGEMENT John D. McDaniels, Jr., Lynchburg, Va., assignor to The Babcock & Wilcox Company, New York, N.Y., a corporation of New Jersey Filed June 12, 1959, Ser. No. 819,948 8 Claims. (Cl. 250-108) This invention relates in general to a storage arrangement and more particularly to a storage arrangement for the storage of radioactive components after their use in a nuclear reactor.

' In the'operation of nuclear reactors certain components contained therein, e.g. spent fuel elements, dummy fuel elements, control rods, and instruments, become radioactive during the course of operation in the radiation flux of the reactor. In periods of maintenance upon the reactor and after such components have become inoperative through use, they must be removed from the reactor and storedin a radiation shielded storage area because of the radiation emitted by decaying fission products formed during operation in the reactor. In the past when such radioactive components have been removed from the reactor, they have been placed in lead shielded containers if the components were small or few in number. When the components were large, or were great in number, they have been consigned to a storage pool in which a large volume of water or other shielding liquid was used to prevent the escape of radiation to the surrounding area.

These former'storage pools, while providing sufficient radiation shielding for the radioactive components, had inherent disadvantages. The pool was usually left uncovered with the attendant possibility of foreign objects accidentally falling into it or, if covered, was provided with unwieldy covers which necessitated mechanical handling apparatus to open the pool for access. In either case, there was little provision for fool-proof indexing of the components within the pool so that but a limited number of spent fuel elements might be adjacently stored. Lacking this storage safeguard, there was always the possibility that several highly radioactive fuel elements might be inadvertently located so as to achieve criticality and undergo an uncontrolled chain reaction. Further, with no cover over the storage pool, or with large or heavy covers, much valuable space was wasted which could otherwise have been used.

The present invention provides a radioactive component storage arrangement with the chamber forming the storage pool provided with a cover having a plurality of slots therethrough. The majority of these slots are storage 3,37,l2% Patented May 29, 1962 age slots. Further, the intermediate portion is selectively dimensioned to permit passage either through the restrictive device in certain of the storage slots or only through storage slots not having the restrictive device. The upper end of the suspension element is adapted to be located and supported by the brackets in the storage slots.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operative advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of the invention.

Of the drawings:

FIG. 1 is a plan view showing the present invention in its relation with a typical reactor plant;

FIG. 2 is a detailed portion of the plan view of the slots in the pool cover;

FIG. 3 is a section taken through a feed slot along line 3-3 of FIG. 2;

FIG. 4 is a section taken through a feed slot along line 4-4 of FIG. 2;

FIG. 5 is another section taken through a feed slot along line 5-5 of FIG. 2.

FIG. 1 shows a plan view of a reactor plant in which the present invention is utilized. A reactor 10 is enclosed in a containment sphere 12 which is penetrated by a transfer tube 14 leading from within the containment sphere 12 to a fuel transfer pool 16 in a fuel handling area 18. Connecting with the fuel transfer pool 16 are a storage pool 20 and other handling pools 22. All of these pools are provided with a cover 24 which serves as a floor to the area above the pools. The pool walls 26 and the pool cover 24 are constructed of reinforced concrete or other suitable structural material. A pick-up slot 28 is provided through the cover of the transfer pool 16 which provides access thereto for the remote handling equipment (not shown) that will handle the radioactive components after their entry into the fuel handling area 18 from the reactor containment sphere 12. The pick-up slot 28 connects with a main feed slot 30 which in turn

interconnects feed slots

32 and 34 of the storage pool 20 and the handling pools 22, respectively. The feed slot 32 in the storage pool communicates with a plurality of storage slots 36 branching off therefrom. Similarly, a plu slots, wherein the stored components are suspended, interconnected by a feeder slot. Brackets are provided at spaced intervals in the storage slots and serve both to locate and support the spent components.

Further, the present invention provides a restrictive device for certain of the storage slots at their juncture with the feeder slot. The pattern of these restrictive devices prevents the storage of spent radioactive fuel elements in adjacent storage slots, thereby eliminating the possibility of inadvertently creating a criticality hazard. The slots, provided with removable closure members, are arranged to provide an imperforate cover for the storage pool.

Additionally, the present invention provides a suspension element adapted to pass through and be positioned longitudinally along the slots in the pool cover. The lower end of this suspension element is adapted to be removab ly attached to the radioactive components which are to be hung therefrom. The intermediate portion is of a length sufficient to keep the entire radioactive component well immersed in the shielding liquid when 'the rality of storage slots 38 branch off of the feed slot 34 in the handling pools 22. Each pool is further provided with an exhaust system 21 between the upper level of the shielding liquid and the pool cover 24 and will be further described hereiubelow.

An enlarged portion of the storage pool cover 24 in FIG. 2 shows part of the feed slot 32 and the storage slots 36. Each slot is provided with a removable closure member 40 which is recessed flush with the top of the pool cover 24 to provide an even floor surface when the closure members are in place. In the illustration, the closure member 40 is shown as being hinged along one edge to the top of the pool cover 24, but other types of removable closure members such as sliding closures, a split closure hinged on both sides of the slot, or a closure member that is completely lifted out of place, may be used.

The exhaust system, shown schematically as 21 in FIG. l,- is provided above the shielding liquid beneath the pool cover 24 to carry off any fission product gases given off by the stored radioactive components therein. Otherwise these gases could escape from the surface of the shielding liquid and find their way through the slots, e.g. 36, in the pool cover 24, around the closure members 40 to the area above, unnecessarily increasing the radiation level. The exhaust system comprises essentially a duct connected to each pool and exhausting through a individual fans at each pool discharging into the duct work to the plant gaseous disposal system.

Each storage slot 36 is provided with a plurality of hanger brackets 42 arranged and secured in pairs along opposite sides of the slots. (See FIGS. 3 and 4.) These hanger brackets, as shown in the preferred embodiment, are substantially U-shaped, as seen in the side view in FIG. 4, and are aligned, one on each side of the slots 36, so that the cut-out portions 44 are oppositely arranged to support the suspension element 46 therefrom. Further, certain of the storage slots 36, e.g. alternate slots, are provided with a restrictive device 48 which is secured to the sides thereof. These devices are positioned at the juncture of the storage slots with the feeder slot 32. (see FIG. 5) to provide selective acceptance of the suspension elements 46 as will be herein described below.

The suspension element 46 is composed of three portions; an upper end portion 50, a lower end portion 52, and an intermediate portion 54. The lower end portion 52 is adapted to be removably attached to the radioactive components (not shown). A simple hooking device is illustrated but any other arrangement, including remote handling apparatus, may be used depending upon the specific application of the present invention. The intermediate portion 54 is an elongated member integrally attached to the lower end portion 52 and the upper end portion 50, and is of a length sufiicient to immerse the radioactive components in the shielding liquid when the upper end portion is slightly above the pool cover 24 during transfer of components. Further, the intermediate portion is selectively sized as indicated by dimensions D and F in FIGS. 3 and 5. One of these dimensions D is such that the intermediate portion 54 will pass freely within the distance C measured betweenthe two oppositely arranged brackets 42 but will not pass within the distance E measured between the restrictive device 48. The other dimension F of the intermediate portion 54 is such that it will pass freely between both the brackets 42 and the restrictive device 48. The upper end portion 50 is integrally attached to the intermediate portion 54 and supports the remainder of the suspension element. The upper end portion 50 is adapted to be handled by the remote handling apparatus (not shown) and is'illustrated by the hole 56, but may be any further adaptation according to the type of handling apparatus employed. The upper end portion has a major dimension 'B such that it will pass within the width A of the storage slot 36 and other slots but not Within the distance C measured between the oppositely arranged bracket 42. The

minor dimension G is such that the upper end portion 50 will seat in the cut-out portion 44 of the brackets 42 so as to locate and support the entire suspension element 46'. a

When the radioactive components are removed from the reactor 10 they are transferred to the fuel transfer pool :16 in the fuel handling area 18 via the transfer tube" 14. They are then secured by the suspension element 46 through the pick-up slot 28. The slot closure members 40 are then opened on the main feed slot 30 and the feed slot 32 of the storage pool 20 and the radioactive components suspended from the suspension element 46 are transferred from the fuel transfer pool 16 to the storage pool 20 by the remote handling apparatus. Duringtliis transfer the suspension element 46 follows the path dictated by the feed slots 30 and 32. with the upper end portion 50 traveling above the pool cover 24 and'th e intermediate portion 54 extending through the slots with the a radioactive components immersed in the shielding liquid of the pool. The closure member 40 for the storage slot 36 to be used is then opened and the suspension element 46 and the radioactive component hung there- 4 from is positioned between a pair of brackets 42 over the cut-out portions 44 thereof. The suspension element 46 is then lowered until the upper end portion 50 is seated in the cut-out portions 44 and the remote han dling apparatus is disconnected to return to the fuel transfer pool 16 for another component to be transferred and stored. The slot closure member 40 is then closed over the storage slot 36 and the radioactive component is stored until further processing is desired, at which time the component is transferred to the handling pools 22 in the same manner as described above. If the radioactive component is highly radio-active or contains fissionable material, e.g. a spent fuel element, the suspension element 46 used for its storage would have an intermediate portion 54 of a dimension D such that it would not pass between E of the restrictive device 48 in the alternate storage slots 36. Non-nuclear components, e.g. spent control rods, are hung from suspension elements 46 having an intermediate portion 54 of a dimension F so that they may be stored in storage slots 36 provided with the restrictive devices 48. 'In this way the possibility of inadvertently storing more than a few highly radioactive components in close proximity with the accompanying criticality hazard is eliminated.

The present invention as described above provides a means of storing radioactive components with a degree of safety heretofore unattained. With the use of the restrictive means in certain of the storage slots and different sized suspension means a relatively foolproof indexing of components of varying radioactivity is attained. In addition, identification of the individual components is easily accomplished by identifying marks placed on the top of the upper end portion '50 of the suspension elements which are easily accessible at the level of the pool cover. Further, with the use of relatively narrow slots through the pool cover and closure members for these slots, unwanted materials are kept out of the pool while providing ease of storage and an imperforate cover giving usable floor area above the pool. In addition, the use of an imperforate cover over the storage pool in co operation with the gaseous exhaust system prevents the escape of little, if any, radioactive vapors that might be given off by the spent components in the shielding liquid.

While in accordance with theprovisions of the statues, I have illustrated and described herein the best form and mode of operation of the invention now known to me, those skilled in the art will understand that changes may be made in the form of the apparatus disclosed without departing from the spirit of the invention covered by my claims, and that certain features of my invention may sometimes be used tov advantage without a corresponding use of other features.

What is claimed is:

1. A storage arrangement for liquid shielded storage of radioactive components, said storage arrangement comprising walls forming a chamber adapted to contain a body of radiation shielding liquid, a cover for said chamber having a plurality of interconnected slots therethrough,

and a suspension means attached at its lower end to said intervals insaid slots, anda suspension means removably attached at its lower end to said radioactive components immersed in said shielding liquid, the upper end of said suspension means adapted to pass through and bepositioned longitudinally along said slots and supported by said brackets.

3. A storage arrangement for liquid shielded storage of radioactive components, said storage arrangement comprising walls forming a chamber adapted to contain a body of radiation shielding liquid, a cover for said chamber having a plurality of narrow interconnected slots therethrough, pairs of brackets located at spaced intervals in said slots, each bracket of said pairs of brackets oppositely arranged one on each side of said slots, and a suspension means removably attached at its lower end to said radioactive components immersed in said shielding liquid, the upper end of said suspension means adapted to pass through and be positioned longitudinally along said slots and supported by said brackets.

4. A storage arrangement for liquid shielded storage of radioactive components, said storage arrangement com prising walls forming a chamber adapted to contain a body of radiation shielding liquid, a cover for said cham her having a plurality of narrow slots therethrough, said slots comprising a feeder slot intercommunicating with a plurality of storage slots branching off therefrom, pairs of U-shaped brackets located at spaced intervals in said storage slots, each bracket of said pairs of Ushaped brackets oppositely arranged and aligned one on each side of said storage slots, and a suspension means removably attached at its lower end to said radioactive components immersed in said shielding liquid, the upper end of each suspension means adapted to pass through and be positioned longitudinally along said slots and supported by said brackets.

5. A storage arrangement for liquid shielded storage of radioactive components, said storage arrangement comprising walls forming a chamber adapted to contain a body of radiation shielding liquid, 21 cover for said chamber having a plurality of narrow slots therethrough, said slots comprising a feeder slot intercommunicating with a plurality of storage slots branching oif therefrom, a removable closure member for each of said storage slots, pairs of U-shaped brackets located at spaced intervals in said storage slots, each bracket of said pairs of U-shaped brackets oppositely arranged and aligned one on each side of said storage slots, and a suspension means removably attached at its lower end to said radioactive components immersed in said shielding liquid, the upper end of said suspension means adapted to pass through and be positioned longitudinally along said slots and supported by said brackets.

6. A storage arrangement for liquid shielded storage of radioactive components, said storage arrangement comprising walls forming a chamber adapted to contain a body of radiation shielding liquid, a cover for said chamber having a plurality of narrow slots therethrough, said slots comprising a feeder slot intercommunicating with a plurality of storage slots branching oil therefrom, a removable closure member for each of said slots adapted to provide an imperforate cover for said chamber, pairs of U-shaped brackets located at spaced intervals in said storage slots, each bracket of said pairs of U-shaped brackets oppositely arranged and aligned one on each side of said storage slots, and a suspension element adapted to support said radioactive components immersed in said shielding liquid, said suspension element having a lower end adapted to be removably attached to said radioactive components and integrally attached to an elongated intermediate portion having a maximum cross-sectional dimension less than that between said oppositely arranged brackets so as to be movably positionable through said slots and to pass between said oppositely arranged U-shaped brackets attached within said storage slots and an upper end portion integrally attached to said intermediate portion, said upper end portion having a major dimension greater than that between said oppositely arranged brack ets and less than that between the two opposite sides of said slots, said upper end portion located and supported by said U-shaped brackets.

6 7. A storage arrangement for liquid shielded storage of radioactive components, said storage arrangement comprising walls forming a chamber adapted to contain a body of radiation shielding liquid, a cover for said chamber having a plurality of narrow slots therethrough, said slots comprising a feeder slot intercommunicating with a plurality of storage slots branching oir" therefrom, a removable closure member for each of said slots adapted to provide an imperforate cover for said chamber, pairs of U-shaped brackets located at spaced intervals in said storage slots, each bracket of said pairs of U-shaped brackets oppositely arranged and aligned one on each side of said storage slots, a restrictive device located in certain storage slots at the junctures thereof with said feeder slot, a suspension element having an upper end portion and a lower end portion integrally attached to an elongated intermediate portion of such a cross-sectional dimension as to permit the passage of the intermediate portion through said restrictive device, said upper end portion adapted to be located and supported by said brackets and having a major dimension greater than that between said oppositely arranged brackets and less than that between the two opposite sides of said slots, said lower end portion adapted to be removably attached to said radioactive components, and a second suspension element having an intermediate portion of a cross-sectional dimension such as to prohibit passage through said restrictive device and yet to permit passage through unrestricted storage slots, said intermediate portion integrally attached to upper and lower end portions similar to those of first said suspension element. 8. A storage arrangement for liquid shielded storage of radioactive components, said storage arrangement comprising walls forming a chamber adapted to contain a body of radiation shielding liquid, a cover for said chamber having a plurality of narrow slots therethrough, said slots comprising a feeder slot intercommunicating with a plurality of storage slots branching off therefrom, a removable closure member for each of said slots adapted to provide an imperforate cover for said chamber, pairs of U-shaped brackets located at spaced intervals in said storage slots, each bracket of said pairs of U-shaped brackets oppositely arranged and aligned one on each side of said storage slots, a restrictive device located in certain storage slots at the junctures thereof with said feeder slot, a suspension element having an upper end portion and a lower end portion integrally attached to an elongated intermediate portion of such a cross-sectional dimension as to permit the passage of the intermediate portion through said restrictive device, said upper end portion adapted to be located and supported by said brackets and having a major dimension greater than that between said oppositely arranged brackets and less than that between the two opposite sides of said slots, said lower end portion adapted to be removably attached to said radioactive components, a second suspension element having an intermediate portion of a cross-sectional dimension such as to prohibit passage through said restrictive device and yet to permit passage through unrestricted storage slots, said intermediate portion integrally attached to upper and lower end portions similar to those of first said suspension element, and an exhaust means adapted to pass through the walls forming said shielding liquid containing chamber between the top of said liquid and said chamber cover, said exhaust means arranged to exhaust the area between the top of said liquid and said chamber cover.

References Cited in the file of this patent UNITED STATES PATENTS 2,851,410 Vernon et al. Sept. 9, 1958 2,857,324 Boisblanc et al. Oct. 21, 1958 2,868,708 Vernon Jan. 13, 1959